Method for protecting the authenticity of an object, item, document, packaging and/or a label from imitation, forgery and theft

Abstract

The invention describes a method for protecting the authenticity of an object, item, document, packaging and/or a label from imitation, forgery and theft, whereas during such marking by means of graphic halftone visually encoded image keeping qualitative-quantitative data of an subject and containing a hidden verification hash code in the form of a digital watermark (DWM), square data cells of the cross-linked structure of the graphic halftone image with identical brightness values are revealed in the entire area inside the revealed square data cell, thereafter a square-cross-linked mask is formed to store the base of the revealed readable data cells, the applied digital watermark (DWM) is read and opposed by means of comparison of the brightness of color components of the central of the revealed readable data cell against the arithmetic mean value of the brightness of the components of the eight neighbor squares surrounding the revealed readable data cell.

Claims

1. A method for protecting authenticity of an object, item, document, packaging, or a label from imitation, forgery and theft, the method comprising: applying security marking onto a surface of the object, item, document, packaging, or label; and verifying authenticity of the object, item, document, packaging or label by reading the marking from the surface of the object, item, document, packaging, or label, wherein applying the security marking on the surface of the object, item, document, packaging, or label includes applying a graphic halftone visually encoded image keeping qualitative-quantitative data of the object, item, document, packaging, or label and containing a hidden verification hash code in the form of a digital watermark (DWM), square data cells of a cross-linked structure of the graphic halftone image with identical brightness values are revealed in an entire area inside a revealed square data cell, the revealed square data cells are conditionally divided into nine equal squares, a digital watermark (DWM) is applied by means of adjustment of the brightness of color components of a central square out of the nine squares of each revealed readable square data cell, identified on the basis of a durable read algorithm depending on the encoded qualitative-quantitative data of the object, item, document, packaging, or label with the use of encoding, hashing and information redundancy algorithms, thereafter a square-cross-linked mask is formed to store a base of the revealed readable square data cells, wherein reading the marking from the surface includes reading the applied digital watermark (DWM) and comparing the brightness of color components of the central square of the revealed readable square data cell against an arithmetic mean value of a brightness of components of eight neighbor squares surrounding the revealed readable square data cell.

2. A method for protecting authenticity of an object, the method comprising: applying security marking onto a surface of the object by: identifying a revealed square data cell within square data cells of a cross-linked structure of the graphic halftone image on the basis of a durable read algorithm based on the encoded data of the object with the use of encoding, hashing, and information redundancy algorithms, the graphic halftone image having identical brightness values such that the revealed square data cell is revealed in an entire area inside the revealed square data cell forming a square-cross-linked mask to store a base of revealed readable square data cells; dividing each of the revealed square data cells into nine equal squares; and adjusting the brightness of color components of a central square of the nine equal squares to apply a digital watermark (DWM) to each of the revealed square data cells; and verifying authenticity of the object by: reading the security marking from the surface of the object by reading the applied digital watermark (DWM); and comparing the brightness of color components of the central square of the revealed readable square data cell against an arithmetic mean value of a brightness of components of eight neighbor squares surrounding the revealed readable square data cell.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The patent or application file contains at least one drawing executed in color. Copies of this patent or patent application publication with color drawing(s) will be provided by the Office upon request and payment of the necessary fee.

(2) FIG. 1 is a graphic halftone image keeping a small amount of qualitative-quantitative data of an object, item and/or document.

(3) FIG. 2 is a halftone image keeping a large amount of qualitative-quantitative data of an object, item and/or document.

(4) FIG. 3 is a cross-linked structure with revealed readable square data cells, applied onto a graphic halftone image with a small amount of data of the object, item and/or document.

(5) FIG. 4 is a cross-linked structure with revealed readable square data cells, applied onto a graphic halftone image with a large amount of data of an object, item and/or document.

(6) FIG. 5 is a conditional scaling of the revealed readable square data cell and identification of the central square as the working area inside the revealed readable square data cell, where in the figure: 1revealed readable square data cell, 2enlarged revealed readable square data cell conditionally divided into nine equal squares (33), 3the central square, one of nine, of the enlarged conditionally divided revealed readable square data cell,

(7) FIG. 6 is an application scheme of digital watermark (DWM) data onto the revealed readable square data cell.

DETAILED DESCRIPTION

(8) The claimed method for protecting the authenticity of an object, item, document, packaging and/or label from imitation, forgery and theft based on marking by means of visually encoded image consists of the following stages:

(9) 1. Identification of the size of qualitative-quantitative data, required for authentification of an object, item, document, packaging and/or label and formation of graphic halftone image containing qualitative-quantitative data of an object, item and/or document.

(10) Halftone image is an image that contains a set of tone values and their continuous, gradual change. Examples of halftone images can be drawings, logos, paintings, photos, which, being raster images, are digitally encoded with the help of a matrix bit map keeping the values of the image elements (pixels).

(11) The marked graphic halftone image contains qualitative-quantitative data of the protected object, item and/or document (name, serial number, expiry date, etc.) in visual form (packaging or label).

(12) If the volume of qualitative-quantitative data of an object, item and/or document is not large, then any halftone image containing qualitative-quantitative data of an object, item and/or document can be used as graphic halftone image. FIG. 1.

(13) If the volume of qualitative-quantitative data is larger than the size of the halftone image able to accommodate a digital watermark (DWM) in itself, then, to increase the volume of protected qualitative-quantitative data of an object, item and/or document, two-dimensional matrix codes are used as graphic halftone image, that are able to contain sufficient amount of data, for instancethe Aztec Code. FIG. 2.

(14) Graphic halftone image is formed with the help of computer raster graphics editor.

(15) 2. Identification of the size of digital watermark (DWM) data and calculation of verification hash code of qualitative-quantitative data of an object, item and/or document.

(16) Digital watermark (DWM) contains a verification hash code of qualitative-quantitative data of an object, item and/or document included in the graphic halftone image. As the data volume contained in the graphic halftone image and the data volume in the digital watermark (DWM) are linearly dependent, but there is no univocal correspondence between initial data and hash sum due to the fact that the amount of hash functions values is smaller than the number of versions of input array values and there are many arrays with different content, but giving identical hash codesthe so called collisions.

(17) Probability of collisions is important for evaluation of the quality of hash functions. There exists a variety of hashing algorithms with different properties, namely: width, computational complexity, cryptosecurity. Selection of one or another hash function is determined by specifics of the task to be solved. Examples of hash codes can be a reference sum or cyclic redundancy code (CRC).

(18) In case if the size of the embedded digital watermark (DWM) data is small and there are suspicions that the stegosystem reliability might be reduced, it is suggested to embed redundancy data or additional noise into the digital watermark (DWM).

(19) For illustration purposes, number 12 selected by pseudorandom-number generator, written in binary form as 1100, is used as a verification hash code.

(20) 3. Allocation and identification of graphic halftone image parts suitable for applying and durable reading of digital watermark (DWM) from the surface of an object, item, packaging, document and/or label.

(21) For identification and allocation of graphic halftone image parts suitable for applying and durable reading of digital watermark (DWM) a cross-linked structure is applied onto the created graphic halftone image containing data of an object, item and/or document, and such square data cells of the cross-linked structure are revealed, the tone brightness values of which are identical in the entire area inside the cell. The revealed square data cells of the cross-linked structure are converted into an ordered square-cross-linked mask, where data are kept about the location of the revealed square cells that are suitable for applying and durable reading of the digital watermark (DWM). The revealed readable square data cells are highlighted in yellow. FIG. 3.

(22) In case, if a two-dimensional matrix code, for instance the Aztec Code, is used as graphic halftone image, such graphic halftone image already contains a cross-linked structure with ordered revealed square cells in the form of Aztec Code elements, that are able to contain a sufficient amount of data about an object, item and/or document. The revealed readable square data cells are highlighted in yellow. FIG. 4.

(23) 4. Applying digital watermark (DWM) onto the revealed readable square data cells of the graphic halftone image.

(24) To embed a digital watermark (DWM) into a graphic halftone image, each revealed readable square data cell (1) of the graphic halftone image is conditionally divided into nine equal squares and as a result of conditional scaling, in the enlarged revealed readable square data cell (2) each central square (3) out of the nine equal squares is identified as the working area of the revealed readable square data cell. FIG. 5.

(25) Applying of digital watermark (DWM) data onto prepared graphic halftone image is performed by modifying the brightness value of the central square (3) out of the nine equal squares of the revealed readable square data cell (2) of the cross-linked structure, where each bit of the verification hash code is assigned to one revealed readable square data cell (1) of the cross-linked structure. The amount of the embedded data of a digital watermark (DWM) in a graphic halftone image depends on the amount of revealed square data cells (1) of the cross-linked structure that are suitable for applying and durable reading of the digital watermark (DWM) and capacity is one data bit per one revealed readable square data cell (1) of the cross-linked structure. The size and amount of revealed readable square data cells of the cross-linked structure are selected by the condition of durable reading of the digital watermark (DWM) by a manual or stationary scanning device for reading and transfer of data subject to its properties.

(26) If a two-dimensional matrix code, for instance, the Aztec Code, is used as graphic halftone image, each element of the Aztec Code is conditionally divided into nine equal squares. The group of 33 equal squares is an element of the Aztec Code and the central square (3)one of the nine equal squares of each Aztec Code element is identified as the working area of the revealed readable square data cell (1) of the cross-linked structure. FIG. 5.

(27) Digital watermark (DWM) is embedded into the Aztec Code by modifying the brightness value of the central square of each Aztec Code element. When forming a graphic halftone image on the Aztec Code example, each data bit of verification hash code is assigned to one light or one dark element of the Aztec Code. The size of embedded data of digital watermark (DWM) in the Aztec Code depends on the number of Aztec Code elements and capacity is one data bit per element.

(28) 5. Method of applying and reading of digital watermark (DWM).

(29) To apply the value of a digital watermark (DWM) hash code onto prepared graphic halftone image, which has {1,1,0,0} bit stream, applying is performed onto revealed readable square data cells of the graphic halftone image or onto revealed Aztec Code elements, shown in this example, before scaling each component {R, G, B} has the value of {0/255,0/255,0/255},this is a black-and-white version of the two-dimensional code. Applying of a digital watermark (DWM) onto a color graphic halftone image is made by analogous method.

(30) Alternatively to the rule of two-dimensional codes' generation, including the Aztec Code, when applying a digital watermark (DWM), the light central square in the area of a light and dark revealed readable square data cell encodes a logical one and the dark central square in the area of the light and dark revealed cell encodes a logical zero. FIG. 6.

(31) Thus, the adjustment of the value of the central square of the revealed readable square data cell or Aztec Code element by some value is needed only in two cases out of four: when embedding one into the square of dark cells (+) and zerointo the square of light cells ().

(32) Adjustment of the value of the central square for each component {R, G, B} in such cases is performed according to Formula 1.

(33) $p_{i,j}^{}=\{\begin{array}{c}{p}_{i,j-},p_{i,j}=255;\\ p_{i,j+},p_{i,j}=0.\end{array}$
where:

(34) P.sub.ijbrightness value of the central square before adjustment;

(35) P.sub.ijbrightness value of the central square after adjustment;

(36) adjustment value, some integral of the (0,127) integral.

(37) Robbing of each data bit of DWM is made according to Formula 2 and Formula 3.

(38) $\stackrel{\text{'}}{}=\frac{\begin{array}{c}{p}_{i-1,j-1}+p_{i-1,j}+p_{i-1,j+1}+\\ p_{i,j-1}+p_{i,j+1}+p_{i+1,j-1}+p_{i+1,j}+p_{i+1,j+1}\end{array}}{8}-p_{i,j}$$m_k=\{\begin{array}{c}1,\stackrel{\text{'}}{}-,\stackrel{\text{'}}{}+p_{\mathrm{ij}}127;\\ 0,\stackrel{\text{'}}{}>-,\stackrel{\text{'}}{}+p_{\mathrm{ij}}127;\\ 0,\stackrel{\text{'}}{},\stackrel{\text{'}}{}+p_{\mathrm{ij}}>127;\\ 1,\stackrel{\text{'}}{}<,\stackrel{\text{'}}{}+p_{\mathrm{ij}}>127;\end{array}$
where:

(39) P.sub.ijbrightness value of the central square after reading;

(40) P.sub.i1 j1, P.sub.i=1 j, P.sub.i1 j+1, P.sub.ij1, P.sub.ij+1, P.sub.i+1 j1,P.sub.i+1 j, P.sub.i+1 j+1brightness value of the neighbor squares after reading;

(41) adjustment value of the central square after reading;

(42) adjustment value from Formula 1;

(43) m.sub.km is a remote DWM bit of variable k.

(44) In practical implementation of the claimed method different adjustment values from 1 to 127 are used and yet a possibility is fixed for reading by standard manual and stationary devices; high percentage of correctly robbed data of the digital watermark (DWM) and visual stability is evaluated as well as resistance against unauthorized replication of graphic halftone image. The selected adjustment value =10 and higher in algorithms of applying and removal of digital watermark (DWM) does not destroy visual stability and simultaneously complies with the requirement for reading the Aztec Code by manual and stationary devices and results in 100% reading of the digital watermark (DWM).

(45) 6. Verification of authenticity of an object, item and/or document by opposing the reading results of the digital watermark (DWM) to the data contained in the cross-linked mask keeping the base of the revealed readable square data cells.

(46) Verification of authenticity of an object, item and/or document is performed by reading the data from graphic halftone image and verification hash code from the digital watermark (DWM), opposing the results and comparing the received data. A positive result of comparison of hash code of input array contained in the graphic halftone image against the read hash sum from the digital watermark (DWM) allows to assert the authenticity of the graphic halftone image.

(47) In case of illegal visual copying of the graphic halftone image distortions of different nature appear, which result in partial loss of the brightness of the read central squares of the digital watermark (DWM), what reflects in the hash function results and allows to assert forgery of an object, item and/or document.

(48) In case of replacement, absence or loss of data or part thereof, as a result of illegal copying of the graphic halftone image or digital watermark (DWM), the result of the verification hash code does not match with the initial value, what gives a possibility to assert the fact of forgery or illegal copying of an object, item and/or document.

(49) At attempt of illegal copying of one or some limited amount of protected images for a whole lot of illegal objects, items and/or documents, verification will reveal repeated serial numbers in the lot of illegal objects, items and/or documents and verification with different geographical coordinates.

(50) Thus, the disclosure enables: 1. performance of applying and reading of marking on the surface of an object, item, document, packaging and/or label by standard manual and stationary devices; 2. significantly improve the reliability of protection and authentication of original objects, items and documents; 3. significantly speed up and facilitate search and detection of thefts; 4. perform recycling of packaging and label with an applied marking and avoid using of special treatment systems; and 5. significantly reduce costs related to authentication of original objects, items and/or documents, for instance: certification of fire-hazardous objects, anti-counterfeit protection of pharmaceuticals and foodstuffs, checking of permits and tickets.